1. Field of the Invention
The present invention relates to a method and an apparatus for treatment of water.
2. Discussion of the Prior Art
Water that is taken into human body for drinking or cooking is required to be treated not to harm human body, and water that is used in direct contact with human body is required to be treated not to bring discomfort to human body. Tap water, in general, is fully sterilized and keep it sterile at faucet which is the distal end of water pipe in order to make it suitable to be taken into human body for drinking, cooking or the like. When raw water is sterilized at a filter plant, the raw water is, in general, treated by strong alkaline sodium hypochlorite (NaOCl) to have less than 100 pieces/mL of coliform bacillus, then is neutralized by hydrochloric acid to a given value between pH 5.8-8.6.
In order to keep tap water in a sterile condition just before using, 1 mg/L of hydrochloric acid remains in tap water. Accordingly, tap water contains a small amount of chlorine (Cl) which triggers cancer, atopic dermatitis and odor. Such water for drinking, cooking, washing human body or bathing is undesirable for a person who is sensitive to chlorine. There are some cases that tap water and well water contain a small amount of such as trihalomethane that is carcinogen or trimethylamine that causes odor, besides chlorine.
Recently, it is attempted in a general household to remove chlorine residue of tap water by using various water treating devices. For example, there have been proposed a method of producing alkaline-ion water suitable for drinking without chlorine residue by using an ionized alkaline water production device, a method of producing water without chlorine residue by activated carbon filtration of tap water, a method of producing water without chlorine residue by fine filtration of tap water in use of a special filtration material such as an ultrafiltration membrane.
In the method of producing ionized alkaline water, particular drinking water such as ionized alkaline water is produced, which is not suitable for general use. In the fine filtration method, it is inevitably required to exchange or reproduce the filtration material such as the activated carbon or ultrafiltration membrane. As the treatment apparatus for these methods is small in size, it is impossible to provide all the water for drinking, cooking, washing human body and bathing at home.